This invention pertains to buoyant structures having particular usefulness in the field of geophysical prospecting. In seismic surveying conducted in connection with offshore oil and gas exploration, it is the practice of the art to have buoyant structures a supporting apparatus such as air gun seismic sources.
The prior art has utilized seismic floats of various materials and dimensions. Thus, large steel floats many feet in length and weighing hundreds or even thousands of pounds and requiring many men to launch such floats from a boat, have been employed. Not only are these metal floats large in size, excessive in weight, high in cost and subject to corrosion which reduces the life expectancy of the floats, but if such a float is damaged, it will sink and thereby disrupt operations and cause delays in scheduled offshore activities. In seeking to overcome this problem of the art in utilizing steel floats, the prior art has provided seismic floats which are relatively light in weight, such as the fiberglass float disclosed in U.S. Pat. No. 3,469,551 or the styrofoam float disclosed in U.S. Pat. No. 3,089,453. While such floats are indeed light in weight, they are not, however, capable of withstanding rough handling. For example, if an air-operative explosive unit is coupled to such a float, the force of the blast may very well destroy the float or at least substantially limit its useful life. Accordingly, not only is there a need in the art for a seismic float which is of reduced weight and thereby easier to handle and to tow than conventional steel seismic floats, but it is also desirable that such seismic floats be relatively rugged and not susceptible to damage either from handling or from air-operative explosive units coupled to the float.